Both agents have been used for management of hypertension during pregnancy. In mild to moderate hypertension methyldopa is the first agent of choice. However, Labetolol is better tolerated and provides rapid blood pressure control, especially in pre-eclampsia. A small study in 1995 compared these 2 agents - see abstract below

Int J Gynaecol Obstet. 1995 May;49(2):125-30.

Labetalol vs. methyldopa in the treatment of pregnancy-induced hypertension.

el-Qarmalawi AM, Morsy AH, al-Fadly A, Obeid A, Hashem M.

Source

Department of Obstetrics and Gynecology, Al-Jahra Hospital, Jahra, Kuwait.

Abstract

OBJECTIVE:

To assess the efficacy and safety of labetalol compared with methyldopa in the management of mild and moderate cases of pregnancy-induced hypertension (PIH).

METHODS:

One hundred four primigravidas with PIH were randomly allocated to receive either labetalol (group A) or methyldopa (group B). The dose of the drugs was doubled every 48 h to maintain a mean arterial blood pressure < or = 103.6 mmHg. Clinico-biochemical effects and frequency of side effects were studied. The statistical level of significance was taken at P < 0.05.

RESULTS:

Ten patients in group B (18.5%) developed significant proteinuria (> 30 mg/dl) whereas none developed proteinuria in group A. Labetalol was quicker and more efficient at controlling blood pressure, having a beneficial effect on renal functions and causing fewer side effects compared with methyldopa. The rate of induction of labor and rate of cesarean section for uncontrolled PIH was less in group A (48% and 1%, respectively) compared with group B (63.0% and 5.6%, respectively). Moreover a higher Bishop score at induction of labor was noticed in group A.

CONCLUSIONS:

Labetalol is better tolerated than methyldopa, gives more efficient control of blood pressure and may have a ripening effect on the uterine cervix.

PMID: 7649315

You can find the latest study here:

http://www.scopemed.org/fulltextpdf.php?mno=34190

Present study showed that labetalol is more advantageous

than methyldopa in terms of better and quicker control of

blood pressure. The chances of spontaneous onset of

labour were greater in the labetalol group than in the

methyldopa group

In preeclampsia the first line anti hypertensive drug is hydralazine infusion in intensive care unit , and if the situation become stable the methyldopa or betablocker as acebutolol were indicated.

In mild preeclampsia, you can give Nicardia, Labetalol or Methyl dopa. If BP is more than 160/110 then rapid normalization is required to prevent stroke. For that Labetalol, Hydralazine on parenteral route should be better. But meticulous titration along with fluid balance is required to prevent fetal demise as well as pulmonary edema. Recently, Level I study showed that Nicardia is better than IV Labetalol in rapid normalization of BP. Only S/E is Tachycardia but incidence is negligible and careful monitoring can prevent it. Expert opinion is that management of BP depends on the experience of obstetrician. However, progression to eclampsia does not depend on normalization of BP (I think) that is why ACOG expert committee suggested to prescribe antihypertensive when BP is more than 160/110 (any one).

Labetalol is better than methyldopa based on the recent study:

Int J Reprod Contracept Obstet Gynecol. 2013; 2(1): 27-34

doi: 10.5455/2320-1770.ijrcog20130205

Comparison of efficacy of labetalol and methyldopa in patients with pregnancy-induced hypertension

Vaidehi Subhedar, Saunitra Inamdar, C. Hariharan, Siddharth Subhedar.

A B S T R A C T R E F E R E N C E S

Abstract

Background: In a country like India, where maternal mortality rate is still very high despite progress and development which has consistently been made in the health services, a big proportion is still deprived of it. Hypertension is the most common medical problem encountered during pregnancy. It is estimated that globally 6-8% of pregnancies are complicated by hypertension. Antihypertensive drugs are often used to lower blood pressure with the aim of preventing its progression to adverse outcomes for the mother and the fetus. The risk of developing severe hypertension is reduced to half by using antihypertensive medications. Hence, this study was planned to assess and compare efficacy of labetalol and methyldopa in controlling blood pressure in patients with PIH and to study maternal and perinatal outcome in rural Indian population.

Methods: 180 patients with PIH were divided in to two groups randomly. After randomization, group A received methyldopa 250 mg tid and group B received labetalol 100mg tid. Mean Arterial pressure (MAP) was calculated according to formula systolic BP +/-2 diastolic BP /3. Patients were subjected to 6 hrly BP monitoring. Comparison of two drugs was done daily by calculating MAP of two groups. Following Observations were made as regards Fall in BP with Labetalol/ Methyldopa, Time required to control BP, Average dose of drugs required to control BP, Onset of labour-spontaneous/induced, Bishop score at induction of labour, Side effects of drugs.

Results: Significant fall in MAP was seen in patients receiving Labetalol. Mean time required to control B.P in group A was 42.22 hours and in group B it was 36.97 hours. Mean Bishop score at induction in present study in group A was 8.27 and in group B was 9.33 with a statistically significant p

mild preeclampsia is better not treated with anti hypertensives to avoid decreasing the blood supply to the fetus as long as not exceeding 140/90 but better for higher pressure less than 160/110 to decrease complications .methyl dopa is better for long time treatment till termination as less complications in mother and fetus than labetalol as IUGR. but severe preeclampsia is better treated by iv hydralazine as rapid and short treatment period and labetalol as second choice

What is the opinion regarding use of antihypertensives in PIH at present? What would be the first line antihypertensive drug?

At what gestation the pregnancy should be terminated in severe hypertension if patient is asymptomatic and all investigations, fudoscopy and ultrasound findings (including Doppler) are normal?